A lighting device of higher heat radiation performance is provided. A lighting device 21 includes: a light guide plate 31 having an end surface 33 as a light entrance surface; a base 40 having an attachment surface 41 that faces the end surface 33 of the light guide plate 31; an LED board 35 having a light emitting surface and provided on the attachment surface 41 such that the light emitting surface faces the end surface 33 of the light guide plate 31; and a pair of heat conduction walls 42 and 43 each arranged on either side of the LED board 35 on the attachment surface 41 of the base 40 and conducting heat generated from the LED board 35 to the base 40. In the lighting device 21, the heat generated form the LED board 35 is conducted to the base side via the heat conduction walls 42 and 43 to be radiated. This enhances heat radiation performance of the LED board 35 that is a heat generation source.